Localization of nodes e.g. mobile devices in wireless communication networks, such as for instance Wi-Fi standards under 802.11x, Bluetooth, Zigbee standards under 802.15x, or any other suitable wireless communication network, has previously been based on so-called round trip time (RTT) measurements for receiving distance information between nodes. However, estimation of RTT of signals sent between nodes in the wireless networks for distance estimations has relevant drawbacks. The precision is poor using RTT due to the involvement of an unknown processing time/time delay in a node after first receiving a message signal from a second node before the signal is sent back to the second node. The processing time is non-deterministic and varies between different devices in a wireless network. Furthermore, such processing times can vary within specific devices due to the work load of the processor.
One solution to the problem of determining an accurate distance between nodes in a wireless communication network would be to exclude the processing time by measuring only the Time of Flight between two nodes. However, this requires that the same time base is used at both nodes, which presents a similar problem as the one described for RTT. Achieving a mutual time base in different nodes requires synchronization between said nodes. Such synchronization is, in a similar way as when measuring RTT, affected by processing times. Thereby, the original problem is recreated.
With the above solutions in mind it would be advantageous to provide a wireless communication network distance determination system that would allow for more accurate distance determinations.